I have a bunch of little glass reed switches. They are fine but the magnets that came with them are substandard. The magnets are metallic (as opposed to ferrite), and 5mm diameter, by 1 mm. They are easily mountable on a bit of wood with heat shrink. I mounted a test one on a pencil, using that method. They are really weak though and you need to place them really close to the switch.
Maybe if I got a set of ferrite, that are about 10mm diameter? I would probably want about 10mm x 10mm x 50mm bit of wood and heat shrink. For the glass reed switch I noticed that you can easily use a terminal block and stretch the switch across about 4 terminals, to avoid breaking the glass. You then have 2 screw holes to work with, for mounting them to a door.
I could do with suggestions on the magnet sizes and materials though.
That may not be a bad idea actually. I think I would still need to use a little block of wood to get the position correct. Even again, I could also use heat shrink, unless I use the holes as the mounting place for screws.
I presume you may have to still be a bit careful how close you put them. Not sure if a stronger one may make the reed stick. Not sure.
Some of those neodymium magnet have a countersunk hole so that the screw head will not stick out.
Using a A flat head screw made of stainless steel or brass is best, since these metals are non-magnetic and will not distort the magnet’s field.
A nylon screw is non-magnetic and non-conductive, so it won’t interfere with the magnetic field either and is lighter if weight matters but nylon is weaker than metal and not ideal if the magnet is large or under mechanical stress.
I have used some with glass reed switches and they worked fine
I would also be concerned about using neodymium magnets with reed switches. They could perhaps damage the reed switches, but they may also activate the reed switches when you don't want them to because of their strong magnetic fields.
I have given this some thought Paul. Maybe one of the reasons why a lot of companies provide specific enclosed units, and specific components (sizes, strength, etc), is because they have done the maths, and used scientific reasoning/ testing.
In that way they have a solution that is going to provide the most efficiency, and good operation. The higher price for industrial setups is likely because they know their stuff, and know the most precise measurements for long life, and efficient running. If a company is using masses of reed switches for things like pneumatic cylinders they must be sure that the equipment is reliable.
Not necessarily true. Do you remember studying magnets in school and the magnetic field around the magnet? A rectangular magnet will trigger a reed switch much better than a round or any other shape magnet because the steel pins in the glass will conduct the magnetic field and close the switch.
The ebike world uses magnets and reed switches (or hall effect sensors) in their brake levers. They are glued in place and sometimes fall out, so replaceable/purchaseable.
When shopping for magnets consider the N-rating. N35 magnet is weak compared to N42, N50, or N52 (the strongest per unit volume of the magnet size). I would think a small magnet of N35, perhaps 1mm thick by 3mm round may be adequate. But buy a small variety and experiment to see what is ideal for your application. Besides size and N-rating, also consider It also how close the magnet will come to the reed switch and at what distance you want it to switch.
